You can create a file without a File Type Extension in Windows 11/10 by carefully following the steps laid down in this post.

However, you can easily create an Outlook PST file on your computer as long as you use the Outlook app. How to create an Outlook PST file To create an Outlook PST file, follow these steps: ...

But if you do have problems booting up your computer as normal, a recovery USB drive can save your system and restore access to your files and apps.